/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.calcite.rex;

import org.apache.calcite.avatica.util.ByteString;
import org.apache.calcite.avatica.util.DateTimeUtils;
import org.apache.calcite.avatica.util.TimeUnit;
import org.apache.calcite.config.CalciteSystemProperty;
import org.apache.calcite.linq4j.function.Functions;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rel.type.RelDataTypeField;
import org.apache.calcite.runtime.FlatLists;
import org.apache.calcite.runtime.SpatialTypeFunctions;
import org.apache.calcite.runtime.variant.VariantValue;
import org.apache.calcite.sql.SqlCollation;
import org.apache.calcite.sql.SqlKind;
import org.apache.calcite.sql.SqlOperator;
import org.apache.calcite.sql.fun.SqlStdOperatorTable;
import org.apache.calcite.sql.parser.SqlParserUtil;
import org.apache.calcite.sql.type.SqlTypeName;
import org.apache.calcite.util.CompositeList;
import org.apache.calcite.util.ConversionUtil;
import org.apache.calcite.util.DateString;
import org.apache.calcite.util.Litmus;
import org.apache.calcite.util.NlsString;
import org.apache.calcite.util.Sarg;
import org.apache.calcite.util.TimeString;
import org.apache.calcite.util.TimeWithTimeZoneString;
import org.apache.calcite.util.TimestampString;
import org.apache.calcite.util.TimestampWithTimeZoneString;
import org.apache.calcite.util.Util;

import com.google.common.collect.ImmutableList;

import org.checkerframework.checker.initialization.qual.UnknownInitialization;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.checkerframework.checker.nullness.qual.PolyNull;
import org.checkerframework.checker.nullness.qual.RequiresNonNull;
import org.checkerframework.dataflow.qual.Pure;
import org.locationtech.jts.geom.Geometry;

import java.io.PrintWriter;
import java.math.BigDecimal;
import java.math.MathContext;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.TimeZone;
import java.util.UUID;

import static com.google.common.base.Preconditions.checkArgument;

import static org.apache.calcite.linq4j.Nullness.castNonNull;
import static org.apache.calcite.rel.type.RelDataTypeImpl.NON_NULLABLE_SUFFIX;

import static java.util.Objects.requireNonNull;

/**
 * Constant value in a row-expression.
 *
 * <p>There are several methods for creating literals in {@link RexBuilder}:
 * {@link RexBuilder#makeLiteral(boolean)} and so forth.
 *
 * <p>How is the value stored? In that respect, the class is somewhat of a black
 * box. There is a {@link #getValue} method which returns the value as an
 * object, but the type of that value is implementation detail, and it is best
 * that your code does not depend upon that knowledge. It is better to use
 * task-oriented methods such as {@link #getValue2} and
 * {@link #toJavaString}.
 *
 * <p>The allowable types and combinations are:
 *
 * <table>
 * <caption>Allowable types for RexLiteral instances</caption>
 * <tr>
 * <th>TypeName</th>
 * <th>Meaning</th>
 * <th>Value type</th>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#NULL}</td>
 * <td>The null value. It has its own special type.</td>
 * <td>null</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#BOOLEAN}</td>
 * <td>Boolean, namely <code>TRUE</code>, <code>FALSE</code> or <code>
 * UNKNOWN</code>.</td>
 * <td>{@link Boolean}, or null represents the UNKNOWN value</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#DECIMAL}</td>
 * <td>Exact number, for example <code>0</code>, <code>-.5</code>, <code>
 * 12345</code>.</td>
 * <td>{@link BigDecimal}</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#DOUBLE},
 *     {@link SqlTypeName#REAL},
 *     {@link SqlTypeName#FLOAT}</td>
 * <td>Approximate number, for example <code>6.023E-23</code>.</td>
 * <td>{@link Double}.</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#DATE}</td>
 * <td>Date, for example <code>DATE '1969-04'29'</code></td>
 * <td>{@link Calendar};
 *     also {@link Calendar} (UTC time zone)
 *     and {@link Integer} (days since POSIX epoch)</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#TIME}</td>
 * <td>Time, for example <code>TIME '18:37:42.567'</code></td>
 * <td>{@link Calendar};
 *     also {@link Calendar} (UTC time zone)
 *     and {@link Integer} (milliseconds since midnight)</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#TIMESTAMP}</td>
 * <td>Timestamp, for example <code>TIMESTAMP '1969-04-29
 * 18:37:42.567'</code></td>
 * <td>{@link TimestampString};
 *     also {@link Calendar} (UTC time zone)
 *     and {@link Long} (milliseconds since POSIX epoch)</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#INTERVAL_DAY},
 *     {@link SqlTypeName#INTERVAL_DAY_HOUR},
 *     {@link SqlTypeName#INTERVAL_DAY_MINUTE},
 *     {@link SqlTypeName#INTERVAL_DAY_SECOND},
 *     {@link SqlTypeName#INTERVAL_HOUR},
 *     {@link SqlTypeName#INTERVAL_HOUR_MINUTE},
 *     {@link SqlTypeName#INTERVAL_HOUR_SECOND},
 *     {@link SqlTypeName#INTERVAL_MINUTE},
 *     {@link SqlTypeName#INTERVAL_MINUTE_SECOND},
 *     {@link SqlTypeName#INTERVAL_SECOND}</td>
 * <td>Interval, for example <code>INTERVAL '4:3:2' HOUR TO SECOND</code></td>
 * <td>{@link BigDecimal};
 *     also {@link Long} (milliseconds)</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#INTERVAL_YEAR},
 *     {@link SqlTypeName#INTERVAL_YEAR_MONTH},
 *     {@link SqlTypeName#INTERVAL_MONTH}</td>
 * <td>Interval, for example <code>INTERVAL '2-3' YEAR TO MONTH</code></td>
 * <td>{@link BigDecimal};
 *     also {@link Integer} (months)</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#CHAR}</td>
 * <td>Character constant, for example <code>'Hello, world!'</code>, <code>
 * ''</code>, <code>_N'Bonjour'</code>, <code>_ISO-8859-1'It''s superman!'
 * COLLATE SHIFT_JIS$ja_JP$2</code>. These are always CHAR, never VARCHAR.</td>
 * <td>{@link NlsString};
 *     also {@link String}</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#BINARY}</td>
 * <td>Binary constant, for example <code>X'7F34'</code>. (The number of hexits
 * must be even; see above.) These constants are always BINARY, never
 * VARBINARY.</td>
 * <td>{@link ByteBuffer};
 *     also {@code byte[]}</td>
 * </tr>
 * <tr>
 * <td>{@link SqlTypeName#SYMBOL}</td>
 * <td>A symbol is a special type used to make parsing easier; it is not part of
 * the SQL standard, and is not exposed to end-users. It is used to hold a flag,
 * such as the LEADING flag in a call to the function <code>
 * TRIM([LEADING|TRAILING|BOTH] chars FROM string)</code>.</td>
 * <td>An enum class</td>
 * </tr>
 * </table>
 */
public class RexLiteral extends RexNode {
  //~ Instance fields --------------------------------------------------------

  /**
   * The value of this literal. Must be consistent with its type, as per
   * {@link #valueMatchesType}. For example, you can't store an
   * {@link Integer} value here just because you feel like it -- all exact numbers are
   * represented by a {@link BigDecimal}. But since this field is private, it
   * doesn't really matter how the values are stored.
   */
  private final @Nullable Comparable value;

  /**
   * The real type of this literal, as reported by {@link #getType}.
   */
  private final RelDataType type;

  /**
   * An indication of the broad type of this literal -- even if its type isn't
   * a SQL type. Sometimes this will be different from the SQL type; for
   * example, all exact numbers, including integers have typeName
   * {@link SqlTypeName#DECIMAL}. See {@link #valueMatchesType} for the
   * definitive story.
   */
  private final SqlTypeName typeName;

  private static final ImmutableList<TimeUnit> TIME_UNITS =
      ImmutableList.copyOf(TimeUnit.values());

  //~ Constructors -----------------------------------------------------------

  /**
   * Creates a <code>RexLiteral</code>.
   */
  RexLiteral(
      @Nullable Comparable value,
      RelDataType type,
      SqlTypeName typeName) {
    this.value = value;
    this.type = requireNonNull(type, "type");
    this.typeName = requireNonNull(typeName, "typeName");
    checkArgument(valueMatchesType(value, typeName, true));
    checkArgument((value == null) == type.isNullable());
    checkArgument(typeName != SqlTypeName.ANY);
    this.digest = computeDigest(RexDigestIncludeType.OPTIONAL);
  }

  //~ Methods ----------------------------------------------------------------

  /**
   * Returns a string which concisely describes the definition of this
   * rex literal. Two literals are equivalent if and only if their digests are the same.
   *
   * <p>The digest does not contain the expression's identity, but does include the identity
   * of children.
   *
   * <p>Technically speaking 1:INT differs from 1:FLOAT, so we need data type in the literal's
   * digest, however we want to avoid extra verbosity of the {@link RelNode#getDigest()} for
   * readability purposes, so we omit type info in certain cases.
   * For instance, 1:INT becomes 1 (INT is implied by default), however 1:BIGINT always holds
   * the type
   *
   * <p>Here's a non-exhaustive list of the "well known cases":
   * <ul><li>Hide "NOT NULL" for not null literals
   * <li>Hide INTEGER, BOOLEAN, SYMBOL, TIME(0), TIMESTAMP(0), DATE(0) types
   * <li>Hide collation when it matches IMPLICIT/COERCIBLE
   * <li>Hide charset when it matches default
   * <li>Hide CHAR(xx) when literal length is equal to the precision of the type.
   * In other words, use 'Bob' instead of 'Bob':CHAR(3)
   * <li>Hide BOOL for AND/OR arguments. In other words, AND(true, null) means
   * null is BOOL.
   * <li>Hide types for literals in simple binary operations (e.g. +, -, *, /,
   * comparison) when type of the other argument is clear.
   * See {@link RexCall#computeDigest(boolean)}
   * For instance: =(true. null) means null is BOOL. =($0, null) means the type
   * of null matches the type of $0.
   * </ul>
   *
   * @param includeType whether the digest should include type or not
   * @return digest
   */
  @RequiresNonNull({"typeName", "type"})
  public final String computeDigest(
      @UnknownInitialization RexLiteral this,
      RexDigestIncludeType includeType) {
    if (includeType == RexDigestIncludeType.OPTIONAL) {
      if (digest != null) {
        // digest is initialized with OPTIONAL, so cached value matches for
        // includeType=OPTIONAL as well
        return digest;
      }
      // Compute we should include the type or not
      includeType = digestIncludesType();
    } else if (digest != null && includeType == digestIncludesType()) {
      // The digest is always computed with includeType=OPTIONAL
      // If it happened to omit the type, we want to optimize computeDigest(NO_TYPE) as well
      // If the digest includes the type, we want to optimize computeDigest(ALWAYS)
      return digest;
    }

    return toJavaString(value, typeName, type, includeType);
  }

  /**
   * Returns whether {@link RexDigestIncludeType} digest would include data type.
   *
   * @see RexCall#computeDigest(boolean)
   * @return whether {@link RexDigestIncludeType} digest would include data type
   */
  @RequiresNonNull("type")
  RexDigestIncludeType digestIncludesType(
      @UnknownInitialization RexLiteral this) {
    return shouldIncludeType(value, type);
  }

  /** Returns whether a value is appropriate for its type. (We have rules about
   * these things!) */
  public static boolean valueMatchesType(
      @Nullable Comparable value,
      SqlTypeName typeName,
      boolean strict) {
    if (value == null) {
      return true;
    }
    switch (typeName) {
    case UUID:
      return value instanceof UUID;
    case VARIANT:
      return value instanceof VariantValue;
    case BOOLEAN:
      // Unlike SqlLiteral, we do not allow boolean null.
      return value instanceof Boolean;
    case NULL:
      return false; // value should have been null
    case INTEGER: // not allowed -- use Decimal
    case TINYINT:
    case SMALLINT:
      if (strict) {
        throw Util.unexpected(typeName);
      }
      // fall through
    case DECIMAL:
    case BIGINT:
      return value instanceof BigDecimal;
    case DOUBLE:
    case FLOAT:
    case REAL:
      return value instanceof Double;
    case DATE:
      return value instanceof DateString;
    case TIME:
    case TIME_WITH_LOCAL_TIME_ZONE:
      return value instanceof TimeString;
    case TIME_TZ:
      return value instanceof TimeWithTimeZoneString;
    case TIMESTAMP:
    case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
      return value instanceof TimestampString;
    case TIMESTAMP_TZ:
      return value instanceof TimestampWithTimeZoneString;
    case INTERVAL_YEAR:
    case INTERVAL_YEAR_MONTH:
    case INTERVAL_MONTH:
    case INTERVAL_DAY:
    case INTERVAL_DAY_HOUR:
    case INTERVAL_DAY_MINUTE:
    case INTERVAL_DAY_SECOND:
    case INTERVAL_HOUR:
    case INTERVAL_HOUR_MINUTE:
    case INTERVAL_HOUR_SECOND:
    case INTERVAL_MINUTE:
    case INTERVAL_MINUTE_SECOND:
    case INTERVAL_SECOND:
      // The value of a DAY-TIME interval (whatever the start and end units,
      // even say HOUR TO MINUTE) is in milliseconds (perhaps fractional
      // milliseconds). The value of a YEAR-MONTH interval is in months.
      return value instanceof BigDecimal;
    case VARBINARY: // not allowed -- use Binary
      if (strict) {
        throw Util.unexpected(typeName);
      }
      // fall through
    case BINARY:
      return value instanceof ByteString;
    case VARCHAR: // not allowed -- use Char
      if (strict) {
        throw Util.unexpected(typeName);
      }
      // fall through
    case CHAR:
      // A SqlLiteral's charset and collation are optional; not so a
      // RexLiteral.
      return (value instanceof NlsString)
          && (((NlsString) value).getCharset() != null)
          && (((NlsString) value).getCollation() != null);
    case SARG:
      return value instanceof Sarg;
    case SYMBOL:
      return value instanceof Enum;
    case ROW:
    case ARRAY:
    case MULTISET:
      return value instanceof List;
    case GEOMETRY:
      return value instanceof Geometry;
    case ANY:
      // Literal of type ANY is not legal. "CAST(2 AS ANY)" remains
      // an integer literal surrounded by a cast function.
      return false;
    default:
      throw Util.unexpected(typeName);
    }
  }

  /**
   * Returns the strict literal type for a given type. The rules should keep
   * sync with what {@link RexBuilder#makeLiteral} defines.
   */
  public static SqlTypeName strictTypeName(RelDataType type) {
    final SqlTypeName typeName = type.getSqlTypeName();
    switch (typeName) {
    case INTEGER:
    case TINYINT:
    case SMALLINT:
      return SqlTypeName.DECIMAL;
    case REAL:
    case FLOAT:
    case DOUBLE:
      return SqlTypeName.DOUBLE;
    case VARBINARY:
      return SqlTypeName.BINARY;
    case VARCHAR:
      return SqlTypeName.CHAR;
    default:
      return typeName;
    }
  }

  private static String toJavaString(
      @Nullable Comparable value,
      SqlTypeName typeName, RelDataType type,
      RexDigestIncludeType includeType) {
    assert includeType != RexDigestIncludeType.OPTIONAL
        : "toJavaString must not be called with includeType=OPTIONAL";
    if (value == null) {
      return includeType == RexDigestIncludeType.NO_TYPE ? "null"
          : "null:" + type.getFullTypeString();
    }
    StringBuilder sb = new StringBuilder();
    appendAsJava(value, sb, typeName, type, false, includeType);

    if (includeType != RexDigestIncludeType.NO_TYPE) {
      sb.append(':');
      final String fullTypeString = type.getFullTypeString();

      if (!fullTypeString.endsWith(NON_NULLABLE_SUFFIX)) {
        sb.append(fullTypeString);
      } else {
        // Trim " NOT NULL". Apparently, the literal is not null, so we just print the data type.
        sb.append(fullTypeString, 0,
            fullTypeString.length() - NON_NULLABLE_SUFFIX.length());
      }
    }
    return sb.toString();
  }

  /**
   * Computes if data type can be omitted from the digest.
   *
   * <p>For instance, {@code 1:BIGINT} has to keep data type while {@code 1:INT}
   * should be represented as just {@code 1}.
   *
   * <p>Implementation assumption: this method should be fast. In fact might call
   * {@link NlsString#getValue()} which could decode the string, however we rely on the cache there.
   *
   * @see RexLiteral#computeDigest(RexDigestIncludeType)
   * @param value value of the literal
   * @param type type of the literal
   * @return NO_TYPE when type can be omitted, ALWAYS otherwise
   */
  private static RexDigestIncludeType shouldIncludeType(@Nullable Comparable value,
      RelDataType type) {
    if (type.isNullable()) {
      // This means "null literal", so we require a type for it
      // There might be exceptions like AND(null, true) which are handled by RexCall#computeDigest
      return RexDigestIncludeType.ALWAYS;
    }
    // The variable here simplifies debugging (one can set a breakpoint at return)
    // final ensures we set the value in all the branches, and it ensures the value is set just once
    final RexDigestIncludeType includeType;
    if (type.getSqlTypeName() == SqlTypeName.BOOLEAN
        || type.getSqlTypeName() == SqlTypeName.INTEGER
        || type.getSqlTypeName() == SqlTypeName.SYMBOL) {
      // We don't want false:BOOLEAN NOT NULL, so we don't print type information for
      // non-nullable BOOLEAN and INTEGER
      includeType = RexDigestIncludeType.NO_TYPE;
    } else if (type.getSqlTypeName() == SqlTypeName.CHAR
            && value instanceof NlsString) {
      NlsString nlsString = (NlsString) value;

      // Ignore type information for 'Bar':CHAR(3)
      if ((
          (nlsString.getCharset() != null
              && Objects.equals(type.getCharset(), nlsString.getCharset()))
          || (nlsString.getCharset() == null
          && Objects.equals(SqlCollation.IMPLICIT.getCharset(), type.getCharset())))
          && Objects.equals(nlsString.getCollation(), type.getCollation())
          && ((NlsString) value).getValue().length() == type.getPrecision()) {
        includeType = RexDigestIncludeType.NO_TYPE;
      } else {
        includeType = RexDigestIncludeType.ALWAYS;
      }
    } else if (type.getPrecision() == 0 && (
               type.getSqlTypeName() == SqlTypeName.TIME
            || type.getSqlTypeName() == SqlTypeName.TIMESTAMP
            || type.getSqlTypeName() == SqlTypeName.DATE)) {
      // Ignore type information for '12:23:20':TIME(0)
      // Note that '12:23:20':TIME WITH LOCAL TIME ZONE
      includeType = RexDigestIncludeType.NO_TYPE;
    } else {
      includeType = RexDigestIncludeType.ALWAYS;
    }
    return includeType;
  }

  /** Returns whether a value is valid as a constant value, using the same
   * criteria as {@link #valueMatchesType}. */
  public static boolean validConstant(@Nullable Object o, Litmus litmus) {
    if (o == null
        || o instanceof BigDecimal
        || o instanceof NlsString
        || o instanceof ByteString
        || o instanceof Boolean) {
      return litmus.succeed();
    } else if (o instanceof List) {
      List list = (List) o;
      for (Object o1 : list) {
        if (!validConstant(o1, litmus)) {
          return litmus.fail("not a constant: {}", o1);
        }
      }
      return litmus.succeed();
    } else if (o instanceof Map) {
      @SuppressWarnings("unchecked") final Map<Object, Object> map = (Map) o;
      for (Map.Entry entry : map.entrySet()) {
        if (!validConstant(entry.getKey(), litmus)) {
          return litmus.fail("not a constant: {}", entry.getKey());
        }
        if (!validConstant(entry.getValue(), litmus)) {
          return litmus.fail("not a constant: {}", entry.getValue());
        }
      }
      return litmus.succeed();
    } else {
      return litmus.fail("not a constant: {}", o);
    }
  }

  /** Returns a list of the time units covered by an interval type such
   * as HOUR TO SECOND. Adds MILLISECOND if the end is SECOND, to deal with
   * fractional seconds. */
  private static List<TimeUnit> getTimeUnits(SqlTypeName typeName) {
    final TimeUnit start = typeName.getStartUnit();
    final TimeUnit end = typeName.getEndUnit();
    final ImmutableList<TimeUnit> list =
        TIME_UNITS.subList(start.ordinal(), end.ordinal() + 1);
    if (end == TimeUnit.SECOND) {
      return CompositeList.of(list, ImmutableList.of(TimeUnit.MILLISECOND));
    }
    return list;
  }

  private String intervalString(BigDecimal v) {
    final List<TimeUnit> timeUnits = getTimeUnits(type.getSqlTypeName());
    final StringBuilder b = new StringBuilder();
    for (TimeUnit timeUnit : timeUnits) {
      final BigDecimal[] result = v.divideAndRemainder(timeUnit.multiplier);
      if (b.length() > 0) {
        b.append(timeUnit.separator);
      }
      final int width = b.length() == 0 ? -1 : width(timeUnit); // don't pad 1st
      pad(b, result[0].toString(), width);
      v = result[1];
    }
    if (Util.last(timeUnits) == TimeUnit.MILLISECOND) {
      while (b.toString().matches(".*\\.[0-9]*0")) {
        if (b.toString().endsWith(".0")) {
          b.setLength(b.length() - 2); // remove ".0"
        } else {
          b.setLength(b.length() - 1); // remove "0"
        }
      }
    }
    return b.toString();
  }

  private static void pad(StringBuilder b, String s, int width) {
    if (width >= 0) {
      for (int i = s.length(); i < width; i++) {
        b.append('0');
      }
    }
    b.append(s);
  }

  private static int width(TimeUnit timeUnit) {
    switch (timeUnit) {
    case MILLISECOND:
      return 3;
    case HOUR:
    case MINUTE:
    case SECOND:
      return 2;
    default:
      return -1;
    }
  }

  /**
   * Prints the value this literal as a Java string constant.
   */
  public void printAsJava(PrintWriter pw) {
    Util.asStringBuilder(pw, sb ->
        appendAsJava(value, sb, typeName, type, true,
            RexDigestIncludeType.NO_TYPE));
  }

  /**
   * Appends the specified value in the provided destination as a Java string. The value must be
   * consistent with the type, as per {@link #valueMatchesType}.
   *
   * <p>Typical return values:
   *
   * <ul>
   * <li>true</li>
   * <li>null</li>
   * <li>"Hello, world!"</li>
   * <li>1.25</li>
   * <li>1234ABCD</li>
   * </ul>
   *
   * @param value    Value to be appended to the provided destination as a Java string
   * @param sb       Destination to which to append the specified value
   * @param typeName Type name to be used for the transformation of the value to a Java string
   * @param type Type to be used for the transformation of the value to a Java string
   * @param includeType Whether to include the data type in the Java representation
   */
  private static void appendAsJava(@Nullable Comparable value, StringBuilder sb,
      SqlTypeName typeName, RelDataType type, boolean java,
      RexDigestIncludeType includeType) {
    switch (typeName) {
    case CHAR:
      NlsString nlsString = (NlsString) castNonNull(value);
      if (java) {
        Util.printJavaString(
            sb,
            nlsString.getValue(),
            true);
      } else {
        boolean includeCharset =
            (nlsString.getCharsetName() != null)
                && !nlsString.getCharsetName().equals(
                CalciteSystemProperty.DEFAULT_CHARSET.value());
        sb.append(nlsString.asSql(includeCharset, false));
      }
      break;
    case BOOLEAN:
      assert value instanceof Boolean;
      sb.append(value);
      break;
    case DECIMAL:
      assert value instanceof BigDecimal;
      sb.append(value);
      break;
    case DOUBLE:
    case FLOAT:
      if (value instanceof BigDecimal) {
        sb.append(Util.toScientificNotation((BigDecimal) value));
      } else {
        assert value instanceof Double;
        Double d = (Double) value;
        String repr = Util.toScientificNotation(d);
        sb.append(repr);
      }
      break;
    case BIGINT:
      assert value instanceof BigDecimal;
      long narrowLong = ((BigDecimal) value).longValue();
      sb.append(narrowLong);
      sb.append('L');
      break;
    case BINARY:
      assert value instanceof ByteString;
      sb.append("X'");
      sb.append(((ByteString) value).toString(16));
      sb.append("'");
      break;
    case NULL:
      assert value == null;
      sb.append("null");
      break;
    case SARG:
      assert value instanceof Sarg;
      //noinspection unchecked,rawtypes
      Util.asStringBuilder(sb, sb2 ->
          printSarg(sb2, (Sarg) value, type));
      break;
    case UUID:
      assert value instanceof UUID;
      sb.append(value);
      break;
    case SYMBOL:
      assert value instanceof Enum;
      sb.append("FLAG(");
      sb.append(value);
      sb.append(")");
      break;
    case DATE:
      assert value instanceof DateString;
      sb.append(value);
      break;
    case TIME:
    case TIME_WITH_LOCAL_TIME_ZONE:
      assert value instanceof TimeString;
      sb.append(value);
      break;
    case TIME_TZ:
      assert value instanceof TimeWithTimeZoneString;
      sb.append(value);
      break;
    case TIMESTAMP:
    case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
      assert value instanceof TimestampString;
      sb.append(value);
      break;
    case TIMESTAMP_TZ:
      assert value instanceof TimestampWithTimeZoneString;
      sb.append(value);
      break;
    case INTERVAL_YEAR:
    case INTERVAL_YEAR_MONTH:
    case INTERVAL_MONTH:
    case INTERVAL_DAY:
    case INTERVAL_DAY_HOUR:
    case INTERVAL_DAY_MINUTE:
    case INTERVAL_DAY_SECOND:
    case INTERVAL_HOUR:
    case INTERVAL_HOUR_MINUTE:
    case INTERVAL_HOUR_SECOND:
    case INTERVAL_MINUTE:
    case INTERVAL_MINUTE_SECOND:
    case INTERVAL_SECOND:
      assert value instanceof BigDecimal;
      sb.append(value);
      break;
    case MULTISET:
    case ROW:
    case ARRAY:
      assert value instanceof List : "value must implement List: " + value;
      @SuppressWarnings("unchecked") final List<RexLiteral> list =
          (List<RexLiteral>) castNonNull(value);
      Util.asStringBuilder(sb, sb2 ->
          Util.printList(sb, list.size(), (sb3, i) ->
              sb3.append(list.get(i).computeDigest(includeType))));
      break;
    case GEOMETRY:
      final String wkt = SpatialTypeFunctions.ST_AsWKT((Geometry) castNonNull(value));
      sb.append(wkt);
      break;
    default:
      assert valueMatchesType(value, typeName, true);
      throw Util.needToImplement(typeName);
    }
  }

  private static <C extends Comparable<C>> void printSarg(StringBuilder sb,
      Sarg<C> sarg, RelDataType type) {
    sarg.printTo(sb, (sb2, value) ->
        sb2.append(toLiteral(type, value)));
  }

  /** Converts a value to a temporary literal, for the purposes of generating a
   * digest. Literals of type ROW and MULTISET require that their components are
   * also literals. */
  private static RexLiteral toLiteral(RelDataType type, Comparable<?> value) {
    final SqlTypeName typeName = strictTypeName(type);
    switch (typeName) {
    case ROW:
      assert value instanceof List : "value must implement List: " + value;
      final List<Comparable<?>> fieldValues = (List) value;
      final List<RelDataTypeField> fields = type.getFieldList();
      final List<RexLiteral> fieldLiterals =
          FlatLists.of(
              Functions.generate(fieldValues.size(), i ->
                  toLiteral(fields.get(i).getType(), fieldValues.get(i))));
      return new RexLiteral((Comparable) fieldLiterals, type, typeName);

    case MULTISET:
    case ARRAY:
      assert value instanceof List : "value must implement List: " + value;
      final List<Comparable<?>> elementValues = (List) value;
      final List<RexLiteral> elementLiterals =
          FlatLists.of(
              Functions.generate(elementValues.size(), i ->
                  toLiteral(castNonNull(type.getComponentType()), elementValues.get(i))));
      return new RexLiteral((Comparable) elementLiterals, type, typeName);

    default:
      return new RexLiteral(value, type, typeName);
    }
  }

  /**
   * Converts a Jdbc string into a RexLiteral. This method accepts a string,
   * as returned by the Jdbc method ResultSet.getString(), and restores the
   * string into an equivalent RexLiteral. It allows one to use Jdbc strings
   * as a common format for data.
   *
   * <p>Returns null if and only if {@code literal} is null.
   *
   * @param type     data type of literal to be read
   * @param typeName type family of literal
   * @param literal  the (non-SQL encoded) string representation, as returned
   *                 by the Jdbc call to return a column as a string
   * @return a typed RexLiteral, or null
   */
  public static @PolyNull RexLiteral fromJdbcString(
      RelDataType type,
      SqlTypeName typeName,
      @PolyNull String literal) {
    if (literal == null) {
      return null;
    }

    switch (typeName) {
    case CHAR:
      Charset charset = requireNonNull(type.getCharset(), () -> "charset for " + type);
      SqlCollation collation = type.getCollation();
      NlsString str =
          new NlsString(
              literal,
              charset.name(),
              collation);
      return new RexLiteral(str, type, typeName);
    case BOOLEAN:
      Boolean b = ConversionUtil.toBoolean(literal);
      return new RexLiteral(b, type, typeName);
    case DECIMAL:
    case DOUBLE:
    case REAL:
    case FLOAT:
      BigDecimal d = new BigDecimal(literal);
      return new RexLiteral(d, type, typeName);
    case BINARY:
      byte[] bytes = ConversionUtil.toByteArrayFromString(literal, 16);
      return new RexLiteral(new ByteString(bytes), type, typeName);
    case NULL:
      return new RexLiteral(null, type, typeName);
    case INTERVAL_DAY:
    case INTERVAL_DAY_HOUR:
    case INTERVAL_DAY_MINUTE:
    case INTERVAL_DAY_SECOND:
    case INTERVAL_HOUR:
    case INTERVAL_HOUR_MINUTE:
    case INTERVAL_HOUR_SECOND:
    case INTERVAL_MINUTE:
    case INTERVAL_MINUTE_SECOND:
    case INTERVAL_SECOND:
      long millis =
          SqlParserUtil.intervalToMillis(
              literal,
              castNonNull(type.getIntervalQualifier()));
      return new RexLiteral(BigDecimal.valueOf(millis), type, typeName);
    case INTERVAL_YEAR:
    case INTERVAL_YEAR_MONTH:
    case INTERVAL_MONTH:
      long months =
          SqlParserUtil.intervalToMonths(
              literal,
              castNonNull(type.getIntervalQualifier()));
      return new RexLiteral(BigDecimal.valueOf(months), type, typeName);
    case DATE:
    case TIME:
    case TIMESTAMP:
      String format = getCalendarFormat(typeName);
      TimeZone tz = DateTimeUtils.UTC_ZONE;
      final Comparable v;
      switch (typeName) {
      case DATE:
        final Calendar cal =
            DateTimeUtils.parseDateFormat(literal,
                new SimpleDateFormat(format, Locale.ROOT), tz);
        if (cal == null) {
          throw new AssertionError("fromJdbcString: invalid date/time value '"
              + literal + "'");
        }
        v = DateString.fromCalendarFields(cal);
        break;
      default:
        // Allow fractional seconds for times and timestamps
        requireNonNull(format, "format");
        final DateTimeUtils.PrecisionTime ts =
            DateTimeUtils.parsePrecisionDateTimeLiteral(literal,
                new SimpleDateFormat(format, Locale.ROOT), tz, -1);
        if (ts == null) {
          throw new AssertionError("fromJdbcString: invalid date/time value '"
              + literal + "'");
        }
        switch (typeName) {
        case TIMESTAMP:
          v = TimestampString.fromCalendarFields(ts.getCalendar())
              .withFraction(ts.getFraction());
          break;
        case TIME:
          v = TimeString.fromCalendarFields(ts.getCalendar())
              .withFraction(ts.getFraction());
          break;
        default:
          throw new AssertionError();
        }
      }
      return new RexLiteral(v, type, typeName);

    case SYMBOL:
      // Symbols are for internal use
    default:
      throw new AssertionError("fromJdbcString: unsupported type");
    }
  }

  private static String getCalendarFormat(SqlTypeName typeName) {
    switch (typeName) {
    case DATE:
      return DateTimeUtils.DATE_FORMAT_STRING;
    case TIME:
      return DateTimeUtils.TIME_FORMAT_STRING;
    case TIMESTAMP:
      return DateTimeUtils.TIMESTAMP_FORMAT_STRING;
    default:
      throw new AssertionError("getCalendarFormat: unknown type");
    }
  }

  public SqlTypeName getTypeName() {
    return typeName;
  }

  @Override public RelDataType getType() {
    return type;
  }

  @Override public SqlKind getKind() {
    return SqlKind.LITERAL;
  }

  /**
   * Returns whether this literal's value is null.
   */
  public boolean isNull() {
    return value == null;
  }

  /**
   * Returns the value of this literal.
   *
   * <p>For backwards compatibility, returns DATE. TIME and TIMESTAMP as a
   * {@link Calendar} value in UTC time zone.
   */
  @Pure
  public @Nullable Comparable getValue() {
    assert valueMatchesType(value, typeName, true) : value;
    if (value == null) {
      return null;
    }
    switch (typeName) {
    case TIME:
    case DATE:
    case TIMESTAMP:
      return getValueAs(Calendar.class);
    default:
      return value;
    }
  }

  /**
   * Returns the value of this literal, in the form that the calculator
   * program builder wants it.
   */
  public @Nullable Object getValue2() {
    if (value == null) {
      return null;
    }
    switch (typeName) {
    case CHAR:
      return getValueAs(String.class);
    case DECIMAL:
    case TIMESTAMP:
    case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
    case TIMESTAMP_TZ:
      return getValueAs(Long.class);
    case DATE:
    case TIME:
    case TIME_WITH_LOCAL_TIME_ZONE:
    case TIME_TZ:
      return getValueAs(Integer.class);
    default:
      return value;
    }
  }

  /**
   * Returns the value of this literal, in the form that the rex-to-lix
   * translator wants it.
   */
  public @Nullable Object getValue3() {
    if (value == null) {
      return null;
    }
    switch (typeName) {
    case DECIMAL:
      assert value instanceof BigDecimal;
      return value;
    default:
      return getValue2();
    }
  }

  /**
   * Returns the value of this literal, in the form that {@link RexInterpreter}
   * wants it.
   */
  public @Nullable Comparable getValue4() {
    if (value == null) {
      return null;
    }
    switch (typeName) {
    case TIMESTAMP:
    case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
      return getValueAs(Long.class);
    case DATE:
    case TIME:
    case TIME_WITH_LOCAL_TIME_ZONE:
      return getValueAs(Integer.class);
    default:
      return value;
    }
  }

  /** Returns the value of this literal as an instance of the specified class.
   *
   * <p>The following SQL types allow more than one form:
   *
   * <ul>
   * <li>CHAR as {@link NlsString} or {@link String}
   * <li>TIME as {@link TimeString},
   *   {@link Integer} (milliseconds since midnight),
   *   {@link Calendar} (in UTC)
   * <li>DATE as {@link DateString},
   *   {@link Integer} (days since 1970-01-01),
   *   {@link Calendar}
   * <li>TIMESTAMP as {@link TimestampString},
   *   {@link Long} (milliseconds since 1970-01-01 00:00:00),
   *   {@link Calendar}
   * <li>DECIMAL as {@link BigDecimal} or {@link Long}
   * </ul>
   *
   * <p>Called with {@code clazz} = {@link Comparable}, returns the value in
   * its native form.
   *
   * @param clazz Desired return type
   * @param <T> Return type
   * @return Value of this literal in the desired type
   */
  public <T> @Nullable T getValueAs(Class<T> clazz) {
    if (value == null || clazz.isInstance(value)) {
      return clazz.cast(value);
    }
    switch (typeName) {
    case UUID:
      if (clazz == String.class) {
        return clazz.cast(((UUID) value).toString());
      }
      break;
    case BINARY:
      if (clazz == byte[].class) {
        return clazz.cast(((ByteString) value).getBytes());
      }
      break;
    case CHAR:
      if (clazz == String.class) {
        return clazz.cast(((NlsString) value).getValue());
      } else if (clazz == Character.class) {
        return clazz.cast(((NlsString) value).getValue().charAt(0));
      }
      break;
    case VARCHAR:
      if (clazz == String.class) {
        return clazz.cast(((NlsString) value).getValue());
      }
      break;
    case DECIMAL:
      if (clazz == Long.class) {
        return clazz.cast(((BigDecimal) value).unscaledValue().longValue());
      }
      // fall through
    case BIGINT:
    case INTEGER:
    case SMALLINT:
    case TINYINT: {
      BigDecimal bd = (BigDecimal) value;
      if (clazz == Long.class) {
        return clazz.cast(bd.longValue());
      } else if (clazz == Integer.class) {
        return clazz.cast(bd.intValue());
      } else if (clazz == Short.class) {
        return clazz.cast(bd.shortValue());
      } else if (clazz == Byte.class) {
        return clazz.cast(bd.byteValue());
      } else if (clazz == Double.class) {
        return clazz.cast(bd.doubleValue());
      } else if (clazz == Float.class) {
        return clazz.cast(bd.floatValue());
      }
      break;
    }
    case DOUBLE:
    case REAL:
    case FLOAT:
      if (value instanceof Double) {
        Double d = (Double) value;
        if (clazz == Long.class) {
          return clazz.cast(d.longValue());
        } else if (clazz == Integer.class) {
          return clazz.cast(d.intValue());
        } else if (clazz == Short.class) {
          return clazz.cast(d.shortValue());
        } else if (clazz == Byte.class) {
          return clazz.cast(d.byteValue());
        } else if (clazz == Double.class) {
          // Cast still needed, since the Java compiler does not understand
          // that T is double.
          return clazz.cast(d);
        } else if (clazz == Float.class) {
          return clazz.cast(d.floatValue());
        } else if (clazz == BigDecimal.class) {
          // This particular conversion is lossy, since in general BigDecimal cannot
          // represent accurately FP values.  However, this is the best we can do.
          // This conversion used to be in RexBuilder, used when creating a RexLiteral.
          return clazz.cast(new BigDecimal(d, MathContext.DECIMAL64).stripTrailingZeros());
        }
      }
      break;
    case DATE:
      if (clazz == Integer.class) {
        return clazz.cast(((DateString) value).getDaysSinceEpoch());
      } else if (clazz == Calendar.class) {
        return clazz.cast(((DateString) value).toCalendar());
      }
      break;
    case TIME:
      if (clazz == Integer.class) {
        return clazz.cast(((TimeString) value).getMillisOfDay());
      } else if (clazz == Calendar.class) {
        // Note: Nanos are ignored
        return clazz.cast(((TimeString) value).toCalendar());
      }
      break;
    case TIME_WITH_LOCAL_TIME_ZONE:
      if (clazz == Integer.class) {
        // Milliseconds since 1970-01-01 00:00:00
        return clazz.cast(((TimeString) value).getMillisOfDay());
      }
      break;
    case TIME_TZ:
      if (clazz == Integer.class) {
        return clazz.cast(((TimeWithTimeZoneString) value).getLocalTimeString().getMillisOfDay());
      }
      break;
    case TIMESTAMP:
      if (clazz == Long.class) {
        // Milliseconds since 1970-01-01 00:00:00
        return clazz.cast(((TimestampString) value).getMillisSinceEpoch());
      } else if (clazz == Calendar.class) {
        // Note: Nanos are ignored
        return clazz.cast(((TimestampString) value).toCalendar());
      }
      break;
    case TIMESTAMP_TZ:
      if (clazz == Long.class) {
        return clazz.cast(((TimestampWithTimeZoneString) value)
            .getLocalTimestampString()
            .getMillisSinceEpoch());
      } else if (clazz == Calendar.class) {
        TimestampWithTimeZoneString ts = (TimestampWithTimeZoneString) value;
        return clazz.cast(ts.getLocalTimestampString().toCalendar(ts.getTimeZone()));
      }
      break;
    case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
      if (clazz == Long.class) {
        // Milliseconds since 1970-01-01 00:00:00
        return clazz.cast(((TimestampString) value).getMillisSinceEpoch());
      } else if (clazz == Calendar.class) {
        // Note: Nanos are ignored
        return clazz.cast(((TimestampString) value).toCalendar());
      }
      break;
    case INTERVAL_YEAR:
    case INTERVAL_YEAR_MONTH:
    case INTERVAL_MONTH:
    case INTERVAL_DAY:
    case INTERVAL_DAY_HOUR:
    case INTERVAL_DAY_MINUTE:
    case INTERVAL_DAY_SECOND:
    case INTERVAL_HOUR:
    case INTERVAL_HOUR_MINUTE:
    case INTERVAL_HOUR_SECOND:
    case INTERVAL_MINUTE:
    case INTERVAL_MINUTE_SECOND:
    case INTERVAL_SECOND:
      if (clazz == Integer.class) {
        return clazz.cast(((BigDecimal) value).intValue());
      } else if (clazz == Long.class) {
        return clazz.cast(((BigDecimal) value).longValue());
      } else if (clazz == String.class) {
        return clazz.cast(intervalString(castNonNull(getValueAs(BigDecimal.class)).abs()));
      } else if (clazz == Boolean.class) {
        // return whether negative
        return clazz.cast(castNonNull(getValueAs(BigDecimal.class)).signum() < 0);
      }
      break;
    default:
      break;
    }
    throw new AssertionError("cannot convert " + typeName
        + " literal to " + clazz);
  }

  public static boolean booleanValue(RexNode node) {
    return (Boolean) castNonNull(((RexLiteral) node).value);
  }

  @Override public boolean isAlwaysTrue() {
    if (typeName != SqlTypeName.BOOLEAN) {
      return false;
    }
    return booleanValue(this);
  }

  @Override public boolean isAlwaysFalse() {
    if (typeName != SqlTypeName.BOOLEAN) {
      return false;
    }
    return !booleanValue(this);
  }

  @Override public boolean equals(@Nullable Object obj) {
    if (this == obj) {
      return true;
    }
    return (obj instanceof RexLiteral)
        && Objects.equals(((RexLiteral) obj).value, value)
        && Objects.equals(((RexLiteral) obj).type, type);
  }

  @Override public int hashCode() {
    return Objects.hash(value, type);
  }

  public static @Nullable Comparable value(RexNode node) {
    return findValue(node);
  }

  /** Returns the value of a literal, cast, or unary minus, as a number;
   * never null. */
  public static Number numberValue(RexNode node) {
    final Comparable value = castNonNull(findValue(node));
    return (Number) value;
  }

  /** Returns the value of a literal, cast, or unary minus, as an int;
   * never null. */
  public static int intValue(RexNode node) {
    final Number number = numberValue(node);
    long longValue = number.longValue();
    if (longValue > Integer.MAX_VALUE || longValue < Integer.MIN_VALUE) {
      throw new ArithmeticException(
          "Integer overflow: " + longValue + " is out of range for INT");
    }
    return number.intValue();
  }

  /** Returns the value of a literal, cast, or unary minus, as a long;
   * never null. */
  public static long longValue(RexNode node) {
    final Number number = numberValue(node);
    return number.longValue();
  }

  public static @Nullable String stringValue(RexNode node) {
    final Comparable value = findValue(node);
    return (value == null) ? null : ((NlsString) value).getValue();
  }

  private static @Nullable Comparable findValue(RexNode node) {
    if (node instanceof RexLiteral) {
      return ((RexLiteral) node).value;
    }
    if (node instanceof RexCall) {
      final RexCall call = (RexCall) node;
      final SqlOperator operator = call.getOperator();
      if (operator == SqlStdOperatorTable.CAST) {
        return findValue(call.getOperands().get(0));
      }
      if (operator == SqlStdOperatorTable.UNARY_MINUS) {
        final BigDecimal value =
            (BigDecimal) findValue(call.getOperands().get(0));
        return requireNonNull(value, () -> "can't negate null in " + node).negate();
      }
    }
    throw new AssertionError("not a literal: " + node);
  }

  public static boolean isNullLiteral(RexNode node) {
    return (node instanceof RexLiteral)
        && (((RexLiteral) node).value == null);
  }

  @Override public <R> R accept(RexVisitor<R> visitor) {
    return visitor.visitLiteral(this);
  }

  @Override public <R, P> R accept(RexBiVisitor<R, P> visitor, P arg) {
    return visitor.visitLiteral(this, arg);
  }
}
